In general, a seat installed rotatably with respect to a vehicle body includes a latching device provided on a leg thereof or the like, and is fastened to the vehicle body by this latching device being engaged with a striker fixed to the vehicle body. A lever for operating the latching device is provided in an appropriate position separate from the latching device for user's convenience of operation, and a pull member such as a wire or a rod is provided between the lever and the latching device, so that the operation of the lever is transmitted to the latching device via the pull member.
Among examples of such a latching device is a latching device developed by the inventor of this application, as described for example in JP 2011-068262 A. This latching device is configured such that a latch engageable with a striker is operable by a latchet, an open lever and an actuating lever, and a wire is engaged with the open lever. Latching/unlatching is done by pulling the wire using the lever or the like located in a position separate from the latching device.
In the latching device configured as described above, the open lever once pulled via the wire makes a rotational motion which is transmitted to the latchet via an actuating arm of the latchet engaged with a groove provided in the open lever. However, the actuating arm of the latchet is retained in engagement with the groove of the open lever before the wire is pulled until the wire has been pulled to the full stroke and thereafter; therefore, there is a possibility that the wire is pulled even under the full-open latch state in which the latch cannot turn any more, and if the wire is pulled hard, an excessive load would be imposed on the latching mechanism, thus requiring a careful consideration to the design of the latch mechanism.
In order to prevent the so-called over-stroke pulling operation which means that a wire is pulled beyond its limit and the wire is held under a great tension, it is customary to make a difference between the length of the wire which can be pulled in the latching mechanism and the length of the wire which can be pulled by the operation of the lever provided for manual operation. However, because the latching device also needs to be designed compactly, it is difficult to ensure that an extra length of the wire (this will be referred to “pull length allowance” in this description) which can be pulled at the manual operation side is provided sufficiently at the latching device side.